Turning 10" peerless sub's into 3-way speakers?

[newboy]

Or turning 2-way bookshelf's into quality full range speakers?
Hi,
My first post on this forum - hope it goes ok.
I have a pair of Peerless XLS 10" (830452) drivers and a pair of matching 10" passive radiators. I would like to use them to build a pair of ('subs') or rather, low frequency boxes (approx 30 litres each) on top of which I would place a pair of high quality 2 way bookshelf speakers (my own handmade DIY dynaudio's, which sound very good). The crossover point for these is about 2650 Hz, so I thought I'd modify the mid driver crossover to a bandpass with a low crossover point of about 260 Hz in order to share the frequency reproduction fairly evenly (& optimally?) between the 3 drivers (dynaudio tweeter, dynaudio 17W75, & peerless 10" + slave).
Hopefully I would end up with a pretty high quality pair of 'modular' full-range stereo speakers, which is what I'm wanting, and definitely NOT a pair of 'cheap thumpers'?
I was wondering if anyone might be able to help me with some queries I have about this proposed project?

1. Would this 'sub' design be suitable for up to about 260 Hz - is this an ok crossover point?
2. Could the passive radiator cone face down or to the rear to enable a lower box height design, as I don't want the overall speaker (with the mid/tweeter box sitting on top) to be too high?
3. Would it be ok to run the "sub's" (& the mid/tweeter's) passively using a pair of NAD power amps (which each produce about 300W RMS into 8 Ohms with low distortion); or would it be better to use dedicated amps for each sub and just use the NAD power amps for the mid/tweeter speakers (a kind of passive mid-high/active low crossover hybrid)? As I would effectively have 2 sub's in the room (which is only medium size), I would imagine the amps would not be over-stretched?
4. I was also thinking of fixing the sub boxes to sandstone blocks to steady everything, as I don't want vibration to interfere with the mid/tweeter boxes - does this sound like a good idea?
5. Thought I might seal up the "vented" dynaudio bookshelf speaker boxes to eliminate port noise, as they would only need to go down to about 200 Hz in this new proposed setup (currently they go down to about 45 Hz), which shouldn't be a drama for a sealed box?
6. Could anyone advise regarding a subsonic (below 18?-25? Hz) high pass filter design for the subs in this proposed setup to protect against over-excursion etc?

Any comments would be GREATLY APPRECIATED!

[sreten]

Hi,

The XLS10 is not a bass unit, it is a subwoofer, and it should be
properly filtered to avoid it messing up the upper bass lower mid.

With these drivers I cannot see the point of anything other than
the usual satellite + subwoofers arrangement. Passive croosovers
wil be very expensive and inflexible and there is no guarantee
sensitivities will match so all in all not a good idea.

Dual 8 ohms subs but one box with a 4 ohm amplifier is an idea.

Read http://www.vandersteen.com/pages/Pdf...%20Reprint.pdf

Note :
I do not agree with everything at all in that article .......
There is a lot of guff about "perfect" c/o's and multiple drivers.

the basics :

The input of the power amplifier has a 1st order high pass.
This can be changing the DC coupling capacitor or a network at the input.
It should be set by ear to get a clean response from the satellites.

You can split at the preamp output or :
The high level subwoofer input should be modified to be the inverse
response of this filter, noting it should not do this down to DC
(which is impossible), but down to the cutoff point of the sub.
The subs high level input is fed from the amplifier output.

The normal controls of the sub are then set to integrate
with what is now the overdamped roll-off of the satellites.

Could look a little like :



/sreten.

[tktran303]

It can be done (Orion, NaO etc), but without measuring equipment it will be very difficult to get good integration with your 2-ways.

The XLS gets kinda funky around 500Hz, which is why most DIYers tend to use this driver crossed low/steep, as a subwoofer.